1. Field of the Invention
This invention relates to a tractor with a cab, and particularly to such a tractor that is used in agricultural operations.
2. Description of the Related Art
Large and medium size agricultural tractors with cabs are widespread. In recent years, there have been increasing demands for small tractors with cabs. In greenhouse cultivation in particular, operations are carried out in an environment of high temperature, a hot and humid environment, or in a dust-laden environment. Such conditions induce a strong desire to drive a tractor with a cab into a greenhouse.
A greenhouse is often designed to have a ceiling of minimum height under such restrictions as a reduction of equipment cost, strength, and a reduction of running cost of a temperature adjuster. It is customary for the greenhouse to have a relative small and low entrance also.
Thus, a tractor with a cab must be constructed to have a small overall height in order to pass through the entrance of the greenhouse. Conventionally, a small overall height of the tractor is achieved by diminishing a wheel diameter or remodeling to provide a higher axle position than in a standard tractor, to be able to enter the greenhouse.
However, the cab tractor with an overall height reduced by the above measure to be movable through a greenhouse entrance has a lowered tractor body carrying a cab of standard size. Such a tractor body has a lower ground clearance than a standard tractor. The tractor with the low tractor body encounters restrictions as to the type of operation outside as well as inside the greenhouse; it cannot ride over ridges that a standard tractor can ride over. For example, the cab tractor with a reduced ground clearance to be able to move into and out of a greenhouse cannot work in a rice field where the wheels subside by large extents. To cope with such a situation, a troublesome operation such as changing of the wheels must be carried out. Thus, the cab tractor with a reduced minimum height has drawbacks in handling convenience and operability.
This invention has been made having regard to the prior art noted above, and its primary object is to provide a tractor with a cab, capable of easily moving into and out of a greenhouse with a low entrance, and having a sufficient ground clearance to be capable of performing a wide variety of operations as is a standard tractor, while securing a sufficient accommodation space for the operator.
Thus, this invention regards, as the starting technique, a tractor having a cab disposed rearwardly of a hood and mounted on a tractor body including a body forming unit, the cab including a bottom wall defining left and right footrests.
A first proposal made by this invention in fulfilling the above object in view of the starting prior art is that the cab has a total length larger than a total height thereof, and the cab is arranged to have the footrests substantially level with a lower end of the body forming unit. With this construction, the entire cab can be installed at a low level relative to the tractor body without reducing the total height of the cab. Since the total length of the cab is larger than the total height thereof, a driver""s seat may be installed relatively rearward to secure a spatial allowance forwardly of the driver""s seat.
A second proposal by this invention is that the cab has a total length larger than a total height thereof, and the cab has an intermediate height level lower than a height level of the hood. With this construction, the entire cab can be installed at a low level relative to the tractor body without reducing the total height of the cab. Here again, a driver""s seat may be installed relatively rearward to secure a spatial allowance forwardly of the driver seated on the driver""s seat.
A third proposal by this invention is that the cab has a total length larger than a total height thereof, the cab is arranged to have the footrests substantially level with a lower end of the body forming unit, and the cab has an intermediate height level lower than a height level of the hood. With this construction, naturally, the entire cab can be installed at a sufficiently low level relative to the tractor body without reducing the total height of the cab. A driver""s seat may be installed relatively rearward to secure a spatial allowance forwardly of the driver seated on the driver""s seat.
In a preferred embodiment of this invention, a hydraulic cylinder provided on a transmission case and usually below the driver""s seat is disposed rearwardly and outside of the cab, whereby a rear portion of the cab may be disposed sufficiently close to an upper surface of the transmission case which is part of the body forming unit. As a result, the driver""s seat disposed in a rearward portion of the cab may be disposed close to the upper surface of the transmission case. That is, the driver""s seat may be disposed in the lowest possible position relative to the tractor body. The top of the cab may be lowered correspondingly.
In another preferred embodiment of the invention, the bottom wall of the cab has a recess formed in a central region thereof and extending in a longitudinally, the body forming unit being disposed in the recess. With this construction, the bottom wall of the cab, which usually is formed substantially flat, is recessed downward, and placed over the body forming unit. Thus, the cab may be installed as lowered relative to the tractor body without excessively reducing the height of the cab itself and without sacrificing the ground clearance of the tractor body. The tractor body including the cab has a reduced overall height while securing an accommodating space free of a feeling of vertical pressure.
In a further preferred embodiment of the invention, the cab has a windshield with an upper portion thereof curved or bent rearward to serve as a front end of a cab ceiling. This construction provides a good upper forward view, and a driving space free of a feeling of pressure.
Further, an air conditioner unit may be disposed in a position other than the ceiling of the cab to allow the cab to be low. Then, the entire tractor may have a reduced height, with the upper end of the cab at a reduced height over the ground, while providing an excellent driving environment. Where the air conditioner unit is disposed forwardly of the driver""s seat, a spatial allowance is secured forwardly of the driver as a precondition. Compared with the case of installing the air conditioner unit in the ceiling of the cab, the upper end of the cab may have a reduced height over the ground while securing a driving space not impairing maneuverability in time of driving.
The cab may be arranged such that the air conditioner unit is disposed in a forward portion of the cab, a hydraulic cylinder is disposed rearwardly and outside of the cab for raising and lowering a working implement, and the driver""s seat disposed in a rearward portion of the cab may be disposed adjacent the upper rear surface of the transmission case. In this case, the entire cab may be installed as lowered relative to the tractor body, with the air conditioner unit disposed forwardly of the driver""s seat. Then, the entire tractor may have a reduced height, with the upper end of the cab at a reduced height over the ground, while providing an excellent driving environment.
The cab may have doors disposed on side planes thereof to be swingable open about hinge axes disposed adjacent the backrest of the driver""s seat in side view. When such a door is opened, a large lateral area of the driver""s seat is opened to facilitate boarding and alighting.
Preferably, the cab tractor according to this invention has a total height of approximately 1.7 m. Then, the tractor may easily move through an entrance of a greenhouse having a standard height (i.e. approximately 1.8 m). Further, the body forming unit may have a ground clearance of approximately 30 cm. This secures a ground clearance comparable to that of a standard tractor. The tractor according to this invention may perform varied operations while straddling ridges inside and outside a greenhouse. This tractor may also engage in a soil puddling operation and the like in a wet field where the wheels could sink to large extents.
Other features and advantages of this invention will be apparent from the following description of the embodiment to be taken with reference to the drawings.